Compressed air supply system and method for determining the parameters of said system

ABSTRACT

The invention relates to a compressed air supply system for motor vehicles comprising a compressed air supply part consisting of a compressor, an air drying part comprising an air dryer, a filter, a valve and a compressed air consumer part consisting of compressed air consumer circuits provided with operational brake circuits, which are supplied with compressed air via a multi-circuit safety valve. The operational brake circuits and optionally, at least one other compressed air consumer circuit comprises compressed air containers and the pressure in said compressed air consumer circuits is monitored by sensors, the electric signals of which are evaluated by an electronic control device. Said electronic control device ( 84 ) is configured in such a manner that in order to determine parameters of the compressed air supply system ( 2 ) and the size of the compressed air containers and the output of the compressor ( 7 ), when filling the compressed air consumer circuits ( 26, 28, 30, 32, 34, 36, 38 ), the compressed air increasing speed in a compressed air consumer circuit and the compressor speed and an air drying regeneration process is carried out after the compressed air consumer circuit is filled with compressed air from the container of said circuit. The time period of a predefined fall in pressure or the fall in pressure is determined over a predefined time period and the amount of air necessary for carrying out said regeneration process is deducted from the value of the fall in pressure, the regeneration time and the known diameter of the filter ( 108 ) and the volume of the container is determined therefrom. The output of the compressor ( 7 ) is determined from the volume of the container, the determined compressed air increasing speed and the compressor speed.

The present invention generally relates to a compressed air supplysystem for motor vehicles according to the preamble of claim 1 as wellas to a method for determining the parameters of the system according tothe preamble of claim 17.

WO 09847751 A1 describes a pneumatic vehicle brake system, which isprovided with a compressor, at least one air-consuming circuit, such asservice brake circuits, a parking brake circuit, a low-pressureauxiliary circuit and a high-pressure circuit, wherein the circuitscontain compressed air tanks and demand valves. Between the compressorand each consuming circuit there is disposed a first electricallyactuatable valve, which is closed in home position, and between thecompressor and the auxiliary circuit there is disposed a secondelectrically actuatable valve, which is open in home position. Thevalves are actuated by an electronic control unit. The output ports ofthe first valves of the air-consuming circuits are in communication viacheck valves with the output port of the second normally open valve.Should a pressure demand be present in one of the circuits, for examplebecause of insufficient tank pressure, the corresponding valve is openedby the control unit and, simultaneously, the second valve of theauxiliary circuit is closed. Failure of the compressor leads to apressure drop, which is recognized by the control unit, which closes thevalves or keeps them closed, thus maintaining the pressure in thecircuits. A pressure regulating valve determines the pressure level. Inthe event of failure of the pressure regulating valve, overpressure isdischarged via an overpressure valve. Pressure sensors monitor thecircuits. The circuits are supplied with air via the second normallyopen valve and via the check valves connected upstream from thecircuits. If the electrical system fails, all valves switch to homeposition. Nevertheless, the compressor continues to run and to supplythe circuits with air via the second normally open valve of theauxiliary circuit, in which case the system pressure is determined by alow-pressure discharge valve of the auxiliary circuit. If a valve fails,the associated circuit can be supplied with air via the valve of theauxiliary circuit and the check valve. The known system is complex,since each consuming circuit is equipped with a compressed air tank.

DE 10004091 C2 describes a compressed air supply device for vehiclecompressed air systems having a multi-circuit protective valve, apressure regulator, a supply line for supplying the circuits of themulti-circuit protective valve with compressed air, and a compressor,which can be switched by means of a pneumatic switching mechanism, apilot valve being provided to control the pressure regulator and theswitching mechanism and a throttle being provided between the pilotvalve and the switching mechanism. Each circuit contains a compressedair tank. The pilot valve is controlled and/or regulated by anelectronic control and/or regulating unit. Pressure sensors monitor thepressure in the circuits and in the supply line.

The known air supply systems have the disadvantage that either they mustbe adjusted mechanically by the manufacturer or they must beparameterized by software.

It is an object of the present invention to optimize the type ofregeneration step described above for an air supply system to the pointthat the air dryer is universally usable.

This object is achieved by the invention according to claims 1 and 17.

Advantageous and expedient embodiments of the invention are specified inthe dependent claims.

The present invention proposes a multi-circuit protective valve havingvalves for the individual consuming circuits and an electronic pressureconditioning system having adaptive behavior for determining thepneumatic layout of the vehicle, such as compressor output capacity,tank configuration, etc. The tank size and compressor output capacityare estimated by determining parameters. For this purpose, in a furtherconfiguration of the invention, an adjustment is made such thatover-regeneration of the air dryer cartridge takes place at least in thefirst regeneration step. The invention optimizes the drying behavior ofthe air dryer and, in this way, achieves reduced energy consumption forcompressed air generation. It is no longer necessary to parameterize theair supply system in a manner corresponding to the pneumatic layout ofthe vehicle. The invention therefore provides a universal air dryer,which can be installed without adaptation in different vehicles. Thevalves of the multi-circuit protective valve may be of mechanical orelectromagnetic type.

The present invention will be discussed in greater detail hereinafter onthe basis of the accompanying drawings, wherein:

FIG. 1 is a basic circuit diagram of a compressed air supply systemhaving a mechanical multi-circuit protective valve in accordance with anembodiment of the present invention;

FIG. 2 is a basic circuit diagram of a compressed air supply systemhaving an electromagnetic multi-circuit protective valve in accordancewith another embodiment of the present invention; and

FIG. 3 is a graphical representation of the determination of tank volumeand compressor output during a first filling of the systems depicted inFIGS. 1 and 2.

Like and corresponding parts in the drawing figures are represented bylike reference numerals.

In the drawings, pressurized fluid lines are represented as solid linesand electrical lines are represented as dashed lines.

FIG. 1 of the drawings shows a compressed air supply system 2 having acompressed air supply part 4 and a consuming part 6. Compressed airsupply part 4 comprises a compressor 7, a compressor control device 8and an air dryer part 10.

Consuming part 6 is provided with a compressed air distributor line 14,which branches out to a plurality of valves 16, 18, 20, 22, 24 and to aplurality of consuming circuits 26, 28, 30, 32, 34 supplied withcompressed air via the valves.

From compressor 7, a compressed air supply line 40 leads via an airdryer cartridge 44, upstream of which there may be connected a filter(not illustrated), and via a check valve 46 to distributor line 14, fromwhich lines 48, 50, 52, 54 branch off and lead to the valves. From thevalves, compressed air lines 58, 60, 62, 64 lead to the consumingcircuits. Line 64 branches out to lines 64′, 64″ leading to circuits 32and 34, line 64′ being branched off to lines 65, 66 leading to consumingcircuits 30, 32. A check valve 68 and a throttle 69 are also disposed inline 65. A pressure limiter 70 is disposed in supply line 54. Valve 24is disposed in line 64″.

Pressure sensors 72, 74, 76, 78, 80 monitor the pressure in theconsuming circuits and transmit the respective pressure as a pressuresignal to an electronic control unit 84, which controls compressed airsupply part 4. The pressure in distributor line 14 may be monitored by apressure sensor (not illustrated).

In addition to the pressure or instead of the pressure, other variablesof state such as air flow, air mass, energy, etc. can also be monitoredor determined in the consuming circuits and in the connecting lines.

As an example, consuming circuits 28, 30 may be service brake circuits;consuming circuit 32 may be a trailer brake circuit and/or a parkingbrake circuit; consuming circuit 34 may be a secondary consumingcircuit, such as, for example, driver's cab suspension, door controller,etc., i.e., nothing that involves the service brake circuits; consumingcircuit 26 may be a high-pressure circuit for an air-suspension system.An air-suspension system normally needs high pressure, because theair-suspension bellows have large volume and relatively high pressures.

Service brake circuits 28, 30 are desirably provided with compressed airtanks (not illustrated) in conformity with the 98/12/EU Directives.High-pressure circuit 26 can also have a compressed air tank.

Compressor 7 is controlled mechanically (pneumatically) via compressorcontroller 8. Compressor controller 8 comprises a solenoid valve 94(having small nominal width), which can be switched by electroniccontrol unit 84 and which in de-energized home condition, asillustrated, is vented. In this condition compressor 7 is turned on andat least one consuming circuit is filled with compressed air. When a setpressure threshold is reached, control unit 84 reverses solenoid valve94, so that compressed air turns off pneumatically actuatable compressor7 via a line 40′. If solenoid valve 94 is switched to de-energizedcondition for refilling in response to air consumption, valve 94 isswitched back to the home condition illustrated in the drawing and line40′ is vented via a line 40″, thus turning on compressor 7. As analternative to the described embodiment, a pneumatically switchablevalve, which in the unactuated home position is vented, can be connecteddownstream from solenoid valve 94 to relieve compressor 7 in theactuated condition.

Air dryer part 10 comprises a regeneration solenoid valve 100 (withsmall nominal width), the input 102 of which is in communication withdistributor line 14 and via the output 104 of which there ispneumatically switched a shutoff valve 106, which is in communicationwith supply line 40 of compressor 7 and serves to relieve thecompressor. Regeneration of air dryer cartridge 44 also takes place viaregeneration valve 100. Line 40 is then open to atmosphere.

When regeneration solenoid valve 100 is in passing condition, compressor7 no longer supplies the consuming circuits but, instead, discharges viavalve 106. Simultaneously, dry air flows out of consuming circuits 26,28, 30 via distributor line 14, solenoid valve 100, throttle 108 andcheck valve 110 through air dryer cartridge 44 for regeneration of itsdesiccant and continues via valve 106.

Reference numeral 112 denotes an overpressure valve.

Valves 16, 18, 20, 22, 24 are mechanical overflow valves, the openingpressures and closing pressures of which are set to correspond to therespective circuits. The pressure in the circuits is monitored directlyat the valves by pressure sensors 72, 74, 86, 78, 80.

FIG. 2 of the drawing shows a compressed air supply system 2 having acompressed air supply part 4 and a consuming part 6. Compressed airsupply part 4 comprises a compressor 7, a compressor control device 8and an air dryer part 10.

Consuming part 6 is provided with a compressed air distributor line 14,a plurality of electrically actuatable solenoid valves 16, 18, 20, 22,24 having restoring springs and a plurality of consuming circuits 26,28, 30, 32, 34, 36, 38 supplied with compressed air via the solenoidvalves.

From compressor 7, a compressed air supply line 40 leads via a filter42, an air dryer cartridge 44 and a check valve 46 to distributor line14, from which lines 48, 50, 52, 54, 56 branch off and lead to thesolenoid valves. From the solenoid valves, compressed air lines 58, 60,62, 64, 66 lead to the consuming circuits. Line 62 branches out to lines62′, 62″ leading to circuits 30 and 32, and a check valve 68 is alsodisposed in line 62″. A pressure limiter 70 is disposed in supply line52. Line 54 leading to solenoid valve 22 branches off downstream frompressure limiter 70. Line 64 branches out to lines 64′, 64″ leading tocircuits 34 and 36.

Pressure sensors 72, 74, 76, 78, 80 monitor the pressure in theconsuming circuits and, if necessary, in distributor line 14 andtransmit the respective pressure as a pressure signal to an electroniccontrol unit 84, which controls compressed air supply part 4.

In addition to the pressure or instead of the pressure, other variablesof state such as air flow, air mass, energy, etc. can also be monitoredor determined in the consuming circuits and in the connecting lines.

As an example, consuming circuits 28, 30 may be service brake circuits;consuming circuit 34 may be a trailer brake circuit, in which casenormally two lines lead to the trailer; consuming circuit 32 may be aparking brake circuit having spring actuators; consuming circuits 36 and38 may be secondary consuming circuits, such as, for example, driver'scab suspension, door controller, etc., i.e., nothing that involves theservice brake circuits; consuming circuit 26 may be a high-pressurecircuit for an air-suspension system.

Service brake circuits 28, 30 are desirably provided with compressed airtanks 90, 92 in conformity with the 98/12/EU Directives. High-pressurecircuit 26 contains a compressed air tank 39. Secondary consumingcircuits 36, 38 may also contain compressed air tanks 36′, 38′(indicated by broken lines).

Compressor 7 is controlled mechanically (pneumatically) via compressorcontroller 8. Compressor controller 8 comprises a solenoid valve 94(having small nominal width), which can be switched by electroniccontrol unit 84 and which in de-energized home position, as illustrated,is vented, and a valve 96, which can be switched pneumatically viasolenoid valve 94 and which, as illustrated, is vented in unactuatedhome position. If compressor 7 is to be turned on, for example because aconsuming circuit needs compressed air, control unit 84 reversessolenoid valve 94, so that pressure acts on control input 98 of thevalve, whereby valve 96 switches back (or is switched) to home conditionand turns on the pneumatically actuatable compressor via a line 40′. Ifsolenoid valve 94 is switched to de-energized condition after thecircuit has been filled, control input 98 is vented via the solenoidvalve, whereby valve 96 switches to its other position and air isadmitted to line 40′, so that compressor 7 is turned off. As analternative, valve 96 can be dispensed with, as in the exemplaryembodiment according to FIG. 1.

Air dryer part 10 comprises a solenoid valve 100 (with small nominalwidth), the input 102 of which is in communication with distributor line14 and via the output 104 of which there is pneumatically switched ashutoff valve 106, which is in communication with supply line 40 ofcompressor 7 and serves to relieve the compressor.

When solenoid valve 100 is in passing condition, compressor 7 no longersupplies the consuming circuits but, instead, discharges via valve 106.Simultaneously, dry air flows out of distributor line 14 (from tanks 90,92 of the service brake circuits), via solenoid valve 100, a throttle108 and a check valve 110 through air dryer cartridge 44 forregeneration of the desiccant and continues via filter 42 and valve 106.

Reference numeral 112 denotes an overpressure valve.

In the inventive compressed air supply system, the compressed air tankvolume and compressor output capacity are determined during a firstfilling by determining the rate of rise of the air pressure in theservice brake circuit, for example, or the time for filling thiscircuit, for which purpose the time of the pressure rise in theassociated tank is measured in control device 84, as a function of thecompressor speed, which depends on the engine speed, from the start ofsupply until a defined upper pressure value p₁ is reached (see curvepart a in FIG. 3).

After the upper pre-definable pressure value p₁ monitored by pressuresensor 74 is reached, compressor 7 is turned off via valve 94, whilesolenoid valve 100 of air dryer part 10 is switched to passingcondition, so that the compressor discharges no longer into line 40 but,instead, via valve 106. Simultaneously, dry air flows from the tank ofcircuit 28 filled to p₁ via distributor line 14, solenoid valve 100,orifice 108 and check valve 110 through air dryer cartridge 44 forregeneration of the desiccant and continues via valve 106.

Regeneration takes place over a time (see curve part b in FIG. 3) inwhich adequate regeneration can be achieved, for example until thepressure in the tank has dropped to a pre-definable value p₂. Since theorifice diameter filled in control device 84 is known, the amount ofcompressed air used for regeneration can be determined from the pressuredrop p₁−p₂, the regeneration time and the orifice diameter. From theamount of compressed air, the orifice diameter and the regenerationtime, control device 84 calculates the tank volume of circuit 28. Fromthe rate of pressure rise, determined as a function of compressor speed,or from the measured filling time in circuit 28, as well as thedetermined compressor speed and the determined volume of circuit 28,control device 84 then calculates the compressor output capacity.

After regeneration of air dryer cartridge 44 by dry air from circuit 28,filling of circuit 28 continues from time t₂ (curve part c) until adefined pressure p₃ is reached at instant t₃. Thereafter, filling ofcircuit 30 additionally takes place while filling of circuit 28continues (curve parts d and e), and, from instant t₄ on, filling ofcircuits 32, 34 (curve part f) also takes place, so that simultaneousfilling of circuits 28, 30, 32, 34 takes place from instant t₄ on.

As soon as the same pressure p₅ is present in circuits 28, 30, 32 and 34(see instant t₅), the rate of pressure rise in circuits 28, 30, 32 and34 is determined as a function of compressor speed until instant t₆.Thereafter, as soon as pressure p₆ is reached at instant t₆, circuits32, 34 are shut off, so that the pressure p₆ in circuits 32, 34 remainsconstant (see straight curve part g). The pressure in circuits 28, 30 isfurther raised (curve part h) until it reaches a pre-definable pressurep₇ (instant t₇). The rate of pressure rise as a function of thecompressor speed is determined in circuits 28 and 30 from the pressuredifference p₇−p₆ and the time t₇−t₆. Thereafter, air dryer cartridge 44is regenerated by dry air from circuits 28 and 30 (curve part i) andthen filling of both circuits continues until they are shut off at apre-defined pressure p₈ in these circuits at instant t₈.

From the already calculated compressor output capacity and thedetermined rate of pressure rise in circuits 28 and 30, the tank volumeof circuits 28 and 30 can then be calculated in the control device.

The tank volume of circuits 28 and 30 can be verified from the amount ofcompressed air needed for regeneration, the known orifice diameter andthe regeneration time.

The described method can be carried out not only for individual tanks orgroups of tanks but also for the total volume of all tanks.

The data determined in the described manner for compressor capacity andtank volumes are saved in the control device. The saved values are usedto monitor the compressor output capacity during driving operation, sothat, in the event of declining output capacity, the regenerationprocess can be adapted to the poorer output capacity and a warningsignal can be generated if necessary. Moreover, the inventive methodmakes it possible to monitor the regeneration orifice for fouling thatcould reduce the orifice diameter, in turn, making it possible for suchfouling to be signaled if necessary.

In case of change or replacement of components of the compressed airsupply system, such as the compressor or a tank, etc., the parameters ofthe compressed air system are re-determined.

Re-determination of the parameters is initiated via a diagnostic unit byprogrammed or manual action.

Instead of the air dryer part and its orifice, or in addition to the airdryer part and its orifice, it is possible to use another pneumaticcomponent having definite and known orifice size for determining theparameters of the compressed air supply system.

1. A compressed air supply system for motor vehicles equipped with acompressed air supply part having a compressor, an air dryer partcomprising an air dryer cartridge, an orifice and a valve, and with acompressed air consuming part having compressed air consuming circuitscomprising service brake circuits, which are supplied with compressedair via a multi-circuit protective valve having a plurality of valves,wherein the service brake circuits and if necessary at least one furthercompressed air consuming circuit are equipped with compressed air tanksand the pressure in the compressed air consuming circuits is monitoredby sensors, whose electrical signals are delivered to an electroniccontrol device and are evaluated thereby, wherein the electronic controldevice (84) is programmed such that, for determination of the parametersof the compressed air supply system (2) in terms of size of thecompressed air tanks and output capacity of the compressor (7) duringfilling of the compressed air consuming circuits (26, 28, 30, 32, 34,36, 38), the rate of rise of air pressure in at least one compressed airconsuming circuit (28, 30, 32) is determined as a function of thecompressor speed, and, after the at least one compressed air consumingcircuit has been filled with compressed air, a step of regeneration ofthe air dryer cartridge is performed from this at least one circuit (28,30, 32), and in the process the time for a pre-definable pressure dropor the pressure drop over a pre-definable time (pressure gradient) isdetermined, after which the amount of air needed for the completedregeneration is calculated from the magnitude of the pressure drop, theregeneration time and the known diameter of the orifice (108) and isthen used to determine the volume of the at least one tank, and finallythe output capacity of the compressor (7) is calculated from the tankvolume and the rate of rise of air pressure determined as a function ofthe compressor speed or from the filling time.
 2. The compressed airsupply system according to claim 1, wherein the filling operation is afirst filling of the compressed air supply system.
 3. The compressed airsupply system according to claim 1 or 2, wherein the rate of rise of airpressure is determined from the time when supply begins until an upperpre-definable pressure threshold value (p₁) associated with theconsuming circuit is reached.
 4. The compressed air supply systemaccording to one of the preceding claims, wherein the regeneration stepis performed over a pre-definable time (t₂−t₁) or until a pre-definablepressure drop (p₁−p₂).
 5. The compressed air supply system according toone of the preceding claims, wherein the pressure drop until apre-definable value takes place above a lower, pre-definable pressurethreshold value associated with the consuming circuit.
 6. The compressedair supply system according to one of the preceding claims, wherein thecompressor output capacity is monitored during driving operation, by thefact that, during a refilling operation to achieve a pre-definablepressurization after consumption of compressed air, the time needed forthis pressurization or the pressure rise achieved within a pre-definabletime is determined and the compressor output capacity is calculated fromthe rate of rise of air pressure calculated therefrom as a function ofthe compressor speed and from the known tank volume.
 7. The compressedair supply system according to one of the preceding claims, wherein awarning signal is generated in the event of a drop of the compressoroutput capacity below a pre-definable value.
 8. The compressed airsupply system according to one of the preceding claims, wherein theregeneration process is adapted to a changing compressor outputcapacity.
 9. The compressed air supply system according to one of thepreceding claims, wherein: during a first filling of the system, aconsuming circuit (28) is filled up to a pre-definable pressure value(p₁), after the pre-definable pressure value (p₁) has been reached, theair dryer valve (100) switches to passing condition for regeneration ofthe desiccant cartridge (44) of the air dryer from circuit (28), thepressure drop that has taken place over a pre-defined regeneration timeor the regeneration time needed for a pre-defined pressure drop isdetermined, the volume of the tank of the circuit (28) is calculatedfrom the regeneration time and the pressure drop, taking intoconsideration the value filed for the diameter of the air dryer orifice(108) and the output capacity of the compressor (7) is calculated fromthe tank volume and from the rate of pressure rise as a function of thecompressor speed.
 10. The compressed air supply system according toclaim 9, wherein, after regeneration of the desiccant cartridge fromcircuit (28), filling of this circuit (28) continues from the instant(t₂) until a defined pressure (p₃) is reached, and in that thereafterfilling of a further circuit (30) additionally takes place and, startingfrom an instant (t₄), filling of a third circuit (32) takes place, sothat simultaneous filling of the circuits (28, 30, 32) takes place fromthe instant (t₄) on.
 11. The compressed air supply system according toclaim 10, wherein the rate of pressure rise in the circuits (28, 30 and32) is determined until an instant (t₆), as soon as the same pressure(p₅) is present in these circuits, and in that thereafter, from instant(t₆) on, at which the pressure has risen to a pre-definable value (p₆),the third circuit (32) is shut off and the rate of pressure rise in thecircuits (28 and 30) is determined until a pre-definable instant (t₇),and in that thereafter the tank volume of the circuits (28 and 30) iscalculated from the rate of pressure rise and the compressor outputcapacity calculated previously via the circuit (28), the rate ofpressure rise being calculated as a function of the compressor speed.12. The compressed air supply system according to one of the precedingclaims 9 to 11, wherein, after the regeneration of the desiccantcartridge from the circuits (28 and 30), the tank volume of the circuits(28 and 30) can be verified from the regeneration time, the pressuredrop and the diameter of the air dryer orifice.
 13. The compressed airsupply system according to one of the preceding claims, wherein thecontrol device (84) is adjusted such that over-regeneration takes placeat least during the first regeneration step.
 14. The compressed airsupply system according to one of the preceding claims, wherein theparameters of the compressed air supply system are re-determined in caseof change or replacement of components of the compressed air supplysystem, such as the compressor or a tank, etc.
 15. The compressed airsupply system according to claim 14, wherein re-determination of theparameters is initiated via a diagnostic unit by programmed or manualaction.
 16. The compressed air supply system according to one of thepreceding claims, wherein, instead of the air dryer part and itsorifice, or in addition to the air dryer part and its orifice, anotherpneumatic component having definite, known orifice size is used fordetermining the parameters of the compressed air supply system.
 17. Amethod for determining the parameters of a compressed air supply systemfor motor vehicles, wherein the compressed air supply system is equippedwith a compressed air supply part having a compressor, an air dryer partcomprising an air dryer cartridge, an orifice and a valve, and with acompressed air consuming part having compressed air consuming circuitscomprising service brake circuits, which are supplied with compressedair via a multi-circuit protective valve having a plurality of valves,wherein the service brake circuits and if necessary at least one furthercompressed air consuming circuit are equipped with compressed air tanksand the pressure in the compressed air consuming circuits is monitoredby sensors, whose electrical signals are delivered to an electroniccontrol device and are evaluated thereby, the method comprising thesteps of: filling the compressed air consuming circuits (26, 28, 30, 32,34, 36, 38), determining the rate of rise of air pressure in at leastone compressed air consuming circuit (28, 30, 32) as a function of thecompressor speed, performing, after the at least one compressed airconsuming circuit has been filled, a step of regeneration of the airdryer cartridge with compressed air from this at least one circuit (28,30, 32), the time of a pre-definable pressure drop or the pressure dropover a pre-definable time (pressure gradient) being determined,determining the amount of air needed for the completed regeneration stepfrom the magnitude of the pressure drop, the regeneration time and theknown diameter of the orifice (108), determining the volume of the atleast one tank, calculating the output capacity of the compressor fromthe tank volume and the rate of rise of air pressure determined as afunction of the compressor speed or from the filling time.
 18. Themethod according to claim 17, wherein the filling operation is a firstfilling of the compressed air supply system.
 19. The method according toclaim 17 or 18, wherein the rate of rise of air pressure is determinedfrom the time when supply begins until an upper pre-definable pressurethreshold value (p₁) associated with the consuming circuit is reached.20. The method according to one of claims 17 to 19, wherein theregeneration step is performed over a pre-definable time (t₂−t₁) oruntil a pre-definable pressure drop (p₁−p₂).
 21. The method according toone of claims 17 to 20, wherein the pressure drop until a pre-definablevalue takes place above a lower, pre-definable pressure threshold valueassociated with the consuming circuit.
 22. The method according to oneof claims 17 to 21, wherein the compressor output capacity is monitoredduring driving operation, by the fact that, during a refilling operationto achieve a pre-definable pressurization after consumption ofcompressed air, the time needed for this pressurization or the pressurerise achieved within a pre-definable time is determined and thecompressor output capacity is calculated from the rate of rise of airpressure calculated therefrom as a function of the compressor speed andfrom the known tank volume.
 23. The method according to one of claims 17to 22, wherein a warning signal is generated in the event of a drop ofthe compressor output capacity below a pre-definable value.
 24. Themethod according to one of claims 17 to 23, wherein the regenerationprocess is adapted to a changing compressor output capacity.
 25. Themethod according to one of claims 17 to 24, wherein: during a firstfilling of the system, a consuming circuit (28) is filled up to apre-definable pressure value (p₁), after the pre-definable pressurevalue (p₁) has been reached, the air dryer valve (100) switches topassing condition for regeneration of the desiccant cartridge (44) ofthe air dryer from circuit (28), the pressure drop that has taken placeover a pre-defined regeneration time or the regeneration time needed fora pre-defined pressure drop is determined, the volume of the tank of thecircuit (28) is calculated from the regeneration time and the pressuredrop, taking into consideration the value filed for the diameter of theair dryer orifice (108) and the output capacity of the compressor (7) iscalculated from the tank volume and from the rate of pressure rise as afunction of the compressor speed.
 26. The method according to claim 25,wherein, after regeneration of the desiccant cartridge from circuit(28), filling of this circuit (28) continues from the instant (t₂) untila defined pressure (p₃) is reached, and in that thereafter filling of afurther circuit (30) additionally takes place and, starting from aninstant (t₄), filling of a third circuit (32) and of a fourth circuit(34) takes place, so that simultaneous filling of the circuits (28, 30,32, 34) takes place from the instant (t₄) on.
 27. The method accordingto claim 24, wherein the rate of pressure rise in the circuits (28, 30,32 and 34) is determined until an instant (t₆), as soon as the samepressure (p₅) is present in these circuits, and in that thereafter, frominstant (t₆) on, at which the pressure has risen to a pre-definablevalue (p₆), the third and fourth circuits (32, 34) are shut off and therate of pressure rise in the circuits (28 and 30) is determined until apre-definable instant (t₇), and in that thereafter the tank volume ofthe circuits (28 and 30) is calculated from the rate of pressure riseand the compressor output capacity calculated previously via the circuit(28), the rate of pressure rise being calculated as a function of thecompressor speed.
 28. The method according to one of claims 25 to 27,wherein, after the regeneration of the desiccant cartridge from thecircuits (28 and 30), the tank volume of the circuits (28 and 30) isverified from the regeneration time, the pressure drop and the diameterof the air dryer orifice.
 29. The method according to one of claims 17to 27, wherein over-regeneration is performed at least during the firstregeneration step.
 30. The method according to one of claims 17 to 29,wherein the parameters of the compressed air supply system arere-determined in case of change or replacement of components of thecompressed air supply system, such as the compressor or a tank, etc. 31.The method according to claim 30, wherein re-determination of theparameters is initiated via a diagnostic unit by programmed or manualaction.
 32. The method according to one of claims 17 to 31, wherein,instead of the air dryer part and its orifice, or in addition to the airdryer part and its orifice, another pneumatic component having definite,known orifice size is used for determining the parameters of thecompressed air supply system.